1. Field of the Invention
The present invention relates to liquid crystal display technology, especially to a sub-pixel display structure which improves color washout phenomenon in 2D display and 3D display, and a liquid crystal display panel using the sub-pixel display structure.
2. Description of the Related Art
Nowadays the liquid crystal display device manufacturer can produce liquid crystal display devices having a size larger than 50 inches. However, large size thin-film transistor liquid crystal display device has an obvious problem with viewing angle, that is, when a user watch the screen of the device from different angles, there are differences in brightness and contrast of the screen. In order to improve the problem of the thin-film transistor LCD with viewing angle, manufacturers has proposed various technologies of wide viewing angle, such as multi-domain vertical alignment (MVA) technology, which effectively increase the viewing angle of the display device. However, although the MVA technology can increase the viewing angle, for a large-sized liquid crystal panel, a problem of color washout will occur at a large viewing angle.
In order to solve the color washout problem, a conventional solution is disclosed in FIG. 1. FIG. 1 is a schematic view of a sub-pixel display structure of a conventional liquid crystal display panel. The sub-pixel display structure includes a first portion 91, a second portion 92, a first scanning line 93, a second scanning line 94, a data line 95, a primary switch unit 96 and a charge-sharing switch 97. The first portion 91 has four liquid crystal domains with different liquid crystal pretilt angles. The second portion 92 also has four liquid crystal domains with different liquid crystal pretilt angles. The first portion 91 and the second portion 92 are disposed between the first scanning line 93 and the second scanning line 94. The first scanning line 93 can switch on the primary switch unit 96 that is correspondingly connected to the first portion 91 and the second portion 92 so that a liquid crystal capacitor in the first portion 91 and a liquid crystal capacitor in the second portion 92 can receive a gray scale voltage from the data line 95 via the primary switch unit 96; the scanning line 94 then switches on the charge-sharing switch 97 so that the liquid crystal capacitor in the second portion 92 further shares electric charges with a voltage-dividing capacitor via the charge-sharing switch. Hence, the liquid crystal capacitor in the first portion 91 and the liquid crystal capacitor in the second portion 92 have different gray scale voltage and thereby have different transmittance and then further improve the color washout phenomenon.
Another solution is disclosed in FIG. 2. The sub-pixel display structure in FIG. 2 includes a first portion 81, a second portion 82, a first data line 83, a second data line 84, a scanning line 85 and a primary switch unit 86. The primary switch unit 86 and the scanning line 85 is disposed between the first portion 81 and the second portion 82. The primary switch unit 86 is connected to the first data line 83 and the second data line 84 and is composed of at least two switches. The scanning line 85 can switch on the primary switch unit 86 so that the first data line 83 and the second data line 84 can transmit different gray scale voltages via the primary switch unit to a liquid crystal capacitor in the first portion 81 and a liquid crystal capacitor in the second portion 82, respectively. In this way, the first portion 81 and the second portion 82 can also have different transmittance to further reduce color washout phenomenon under large viewing angles.
With the development of liquid crystal display technology, manufacturers also develop liquid crystal display panels providing 3D display function, such as a liquid crystal display panel using a patterned phase retarder film can have a 3D display function. However, when the sub-pixel structure in FIG. 1 or in FIG. 2 is adopted in the liquid crystal display panel having a patterned phase retarder film, an interval between a sub-pixel structure for displaying left-eye images and a sub-pixel structure for displaying right-eye images must be widened so as to avoid image crosstalk. Thus, the sub-pixel structure in FIG. 1 or in FIG. 2 has to partially dispose black matrix on the pixel portions or switch off the display function of one of the pixel portions (so as to act as a black matrix) to satisfy the requirement of 3D viewing angle and thereby causing the liquid crystal display panel to be unable to solve the color washout problem under 3D display.
Therefore, some manufacturers further disclose a sub-pixel display structure as shown in FIG. 3. The sub-pixel display structure includes a first portions 71, a second portion 72, a third portion 73, a first data line 74, a second data line 75, a first scanning line 76, a second scanning line 77, a primary switch unit 78 and a charge-sharing switch 79. The first scanning line 76 and the primary switch unit 78 are disposed between the first portion 71 and the second portion 72. The primary switch unit 78 is composed of three switches. The first scanning line 76 can switch on the primary switch unit 78 to further make the liquid crystal capacitor in the first portion 71 to receive a gray scale voltage inputted by the second data line 75 and make the liquid crystal capacitors in the second portion 72 and the third portion 73 to receive a gray scale voltage inputted by the first data line 74. Since the first date line 74 and the second data line 75 transmit different gray scale voltages, the first portion 71 and the second portion 72 or the third portion 73 can have different transmittance to further improve color washout at large viewing angles under 2D display. Besides, under 3D display, the first portion 71 can be switched off to act as a black matrix so as to satisfy the requirement of 3D viewing angle; in the meantime, the second scanning line 77 can switch on the charge-sharing switch 79 such that the liquid crystal capacitor in the third portion 73 further shares electric charges with a voltage-dividing capacitor via the charge-sharing switch 79. In this way the liquid crystal capacitor in the second portion 72 and the liquid crystal capacitor in the third portion 73 can respectively have different gray scale voltages to have different transmittance. Hence, the liquid crystal display panel can still reduce the color washout phenomenon at large viewing angles under 3D display.
However, the sub-pixel display structure in FIG. 3 has to use two data lines at the same time, and since the manufacturing cost and power consumption of a data driving chip (also called source driving chip) is relatively higher, the sub-pixel display structure in FIG. 3 will relatively increase the manufacturing cost and power consumption of the liquid crystal display device.
Therefore, it is necessary to provide a sub-pixel display structure and an inspection method using the same to overcome the problems existing in the conventional technology.